The invention concerns a device for the heat treatment of a continuously guided material web, in particular a textile web, such devices, also called nozzle driers and convection dryers, have been known and in use for a long time in the textile industry for the treatment of woven and knitted fabrics. It is usual that heated, ambient air is used as a treatment medium, and that in certain cases other gaseous mediums or mixtures are employed.
A related and comparable device is, for example, made known in German Auslegenschrift DD-A-255 201. A problem with known devices is that a turbulent flow exists in the housing, and in particular also in the nozzle casings, which leads to irregular temperature distribution and thus an unsatisfactory drying result. Apart from that, the individual nozzle casings are only accessible from the outside with difficulty, and heat efficiency of the system as a whole is relatively poor, in spite of the use of insulating material.